title: The relationship between cortical excitability and pain catastrophizing in myofascial pain.
abstract: Pain catastrophizing regularly occurs in chronic pain patients. It has been suggested that pain catastrophizing is a stable, person-based construct. These findings highlight the importance of investigating catastrophizing in conceptualizing specific approaches for pain management. One important area of investigation is the mechanism underlying pain catastrophizing. Therefore, this study explored the relationship between a neurophysiological marker of cortical excitability, as assessed by transcranial magnetic stimulation, and catastrophizing, as assessed by the Brazilian Portuguese Pain Catastrophizing Scale, in patients with chronic myofascial pain syndrome. The Pain Catastrophizing Scale is a robust questionnaire used to examine rumination, magnification and helplessness that are associated with the experience of pain. We include 24 women with myofascial pain syndrome. The Brazilian Portuguese Pain Catastrophizing Scale and cortical excitability were assessed. Functional and behavioral aspects of pain were evaluated with a version of the Profile of Chronic Pain scale and by multiple pain measurements (eg, pain intensity, pressure pain threshold, and other quantitative sensory measurements). Intracortical facilitation was found to be significantly associated with pain catastrophizing (β = .63, P = .001). Our results did not suggest that these findings were influenced by other factors, such as age or medication use. Furthermore, short intracortical inhibition showed a significant association with pressure pain threshold (β = .44, P = .04). This study elaborates on previous findings indicating a relationship between cortical excitability and catastrophizing. The present findings suggest that glutamatergic activity may be associated with mechanisms underlying pain catastrophizing; thus, the results highlight the need to further investigate the neurophysiological mechanisms associated with pain and catastrophizing.
  
  
  
  This study highlights the relationship between cortical excitability and catastrophizing. Cortical measures may illuminate how catastrophizing responses may be related to neurophysiological mechanisms associated with chronic pain.
authors.affiliation: Laboratory of Pain and Neuromodulation, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil; Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, Massachusetts; Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Magdalena Sarah
authors.initials: MS
authors.lastname: Volz
authors.forename: Liciane F
authors.initials: LF
authors.lastname: Medeiros
authors.forename: Maria da Graça
authors.initials: Mda G
authors.lastname: Tarragô
authors.forename: Liliane P
authors.initials: LP
authors.lastname: Vidor
authors.forename: Letizzia
authors.initials: L
authors.lastname: Dall'Agnol
authors.forename: Alicia
authors.initials: A
authors.lastname: Deitos
authors.forename: Aline
authors.initials: A
authors.lastname: Brietzke
authors.forename: Joanna R
authors.initials: JR
authors.lastname: Rozisky
authors.forename: Bruna
authors.initials: B
authors.lastname: Razzolini
authors.forename: Iraci L S
authors.initials: IL
authors.lastname: Torres
authors.forename: Felipe
authors.initials: F
authors.lastname: Fregni
authors.forename: Wolnei
authors.initials: W
authors.lastname: Caumo
mesh_terms: D000328:Adult; D000368:Aged; D058443:Catastrophization / Q000523:psychology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D059350:Chronic Pain; D003863:Depression / Q000523:psychology; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology; D009209:Myofascial Pain Syndromes / Q000503:physiopathology* / Q000523:psychology*; D009483:Neuropsychological Tests; D010147:Pain Measurement; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D050781:Transcranial Magnetic Stimulation
keywords: Catastrophizing; Quantitative Sensory Testing; chronic pain; cortical excitability; glutamatergic system; myofascial pain; repetitive transcranial magnetic stimulation